1. Field of the Invention
The present invention relates to a brush with bristles extending radially from a core such as a twisted wire core. More particularly, the invention concerns a device and method for arranging the radially extending bristles of a brush, such as a brush for applying mascara.
2. Description of the Prior Art
Brushes, such as, for example, mascara brushes used to apply mascara to a user's eyelashes, are known. A common type of mascara brush is comprised of a core formed from a single metallic wire folded in a generally unshaped configuration to provide a pair of parallel wire segments. Bristles (sometimes referred to as filaments), usually comprised of strands of nylon, are disposed between a portion of a length of the wire segments. The wire segments are then twisted, or rotated, to form a twisted wire core, which holds the filaments substantially at their midpoints so as to clamp them between the wire segments. In this way, a bristle portion or bristle head is formed with radially extending bristles secured to the twisted wire core in a spiral manner. See, for example, U.S. Pat. No. 4,887,622 to Gueret; and U.S. Pat. No. 4,733,425 to Hartel et al.
Generally, a mascara applicator is inserted into a container having a reservoir of mascara or some other cosmetic medium. The bristles are arranged so as to pick up a supply of mascara and carry it from the container for application to a user's eyelashes. See, for example, U.S. Pat. No. 4,365,642 to Costa; U.S. Pat. No. 4,733,425 to Hartel et al.; and U.S. Pat. No. 4,887,622 to Gueret. These mascara applicators are said to maximize the amount of mascara carried by the applicator and are said to apply the mascara in a uniform and attractive manner, while simultaneously combing the eyelashes in a desired fashion.
These and other objectives are generally considered to be important in mascara brush design. As noted, brushes are preferred that maximize the amount of mascara picked up by the applicator from the mascara reservoir for application to the eyelashes, thus minimizing the number of times a user must introduce the applicator into the reservoir to replenish the brush. Brushes are also preferred that apply the mascara in a uniform manner and simultaneously comb the lashes to separate and remove excess mascara from the lashes. For the convenience of the user, application and combing of lashes is preferably accomplished in as few strokes as possible, with as few introductions of the applicator into the mascara reservoir as possible.
Because cosmetic product characteristics vary, a brush design that is ideal for use with one particular cosmetic product may not be suitable for use with another cosmetic product. For example, a particular mascara formulation may be thicker, or may contain more solids, thus requiring brush characteristics different from those required by a thinner product or a product containing fewer solids.
In addition, users may favor one brush characteristic over another. For example, a user may prefer a brush that combs well but carries less product.
It is known that modifying the stiffness of the bristles or the distribution of the bristle tips of a conventional-type twisted wire brush can significantly alter, for example, the retention, application and/or combing characteristics of the brush, and may improve the esthetic appeal of the brush. For example, U.S. Pat. No. 4,733,425 to Hartel et al. discloses the use of hollow bristles or bristles having a non-circular cross-section to yield an improved bristle distribution. U.S. Pat. No. 4,861,179 to Schrepf et al. discloses soft and stiff bristles intermingled throughout the length of a brush in specified proportion so that the brush may be used both for applying mascara and combing the eyelashes. U.S. Pat. No. 5,657,778 to Gueret discloses the use of bristles having a transverse section in the shape of an L, which is said to yield an improved bristle distribution. U.S. Pat. No. 5,161,555 to Cansler et al. discloses a brush utilizing heavily waved bristles instead of straight bristles, which is said to more evenly distribute the ends of the bristles.
The known brushes, including the foregoing examples, rely on unique bristle structure (e.g., hollow, non-circular or I-shaped section) or unique bristle characteristics (e.g., intermingled soft and stiff bristles) to modify brush characteristics. Generally, the use of unique bristle components incurs higher unit costs due to higher initial cost for the components, and increased assembly costs due to unique production and process issues, e.g., the difficulty of handling heavily waved bristles. In addition, the use of a unique component may yield undesired brush characteristics or limit the degree to which brush characteristics can be modified.
Brushes are also known wherein a bristle carrying strip is arranged spirally about a core. For example, U.S. Pat. Nos. 4,490,877 to Drumm and 3,998,235 to Kingsford (FIGS. 5-6) disclose a bristle carrying strip in the form of a U-shaped channel supporting bristles. In each disclosed brush, the channel is spirally wound around a support. U.S. Pat. No. 4,114,221 to Enchelmaier discloses a bristle carrying strip with notches supporting tufts of bristles. The strip is spirally wound about a core. In each of these three disclosures, the bristles are fixed to the spiral strip, not to the core of the brush. Because the bristles are fixed to the spiral strip, the degree to which bristle distribution can be modified is limited, for example, to changes in pitch of the spiral. Furthermore, there is no indication that the disclosed structures can be used to modify the bristle distribution of an existing conventional mascara brush.
Accordingly, there is a need for a low cost brush wherein the bristle distribution can be dramatically modified during or after production, also at low cost, to meet a variety of functional and esthetic objectives.